Question

In an experiment ethyliodide in ether is allowed to stand over magnesium pieces. Magnesium dissolves and product is formed

1. Name the product and write the equation for the reaction.
2. Why all the reagents used in the reaction should be dry? Explain.
3. How is acetone prepared from the product obtained in the experiment.

Answer 1

1. Name of the product and write the equation for the reaction.
   \[\ce{CH3I + Mg ->[ether] CH3Mgl}\]
2. All the reagents used in the reaction should be dry because reagent reacts with H20 to produce alkane. This is the reason that everything has to be very dry during the preparation of Grignard reagents.
   \[\begin{array}{cc}\phantom{..................................}\ce{I}\\
   \phantom{................................}/\\
   \ce{\underset{\text{Methane}}{CH3 - Mgl} + H2O -> CH4 + Mg}\\
   \phantom{................................}\backslash\\
   \phantom{..................................}\ce{OH}
   \end{array}\]
3. \[\begin{array}{cc}
   \phantom{.....................................}\ce{CH3}\phantom{....................................}\ce{I}\\
   \phantom{.....................................}|\phantom{......................................}/\\
   \ce{CH3 - C = O + CH3Mgl -> CH3 - C - OMgl ->[H+/H2O] CH3 - C - CH3 + Mg}\\
   \phantom{...........}|\phantom{.............................}|\phantom{.........................}||\phantom{............}\backslash\phantom{....}\\
   \phantom{...........}\ce{\underset{\text{Acetyl chloride}}{Cl}}\phantom{........................}\ce{Cl}\phantom{.......................}\ce{\underset{\text{Acetone}}{O}}\phantom{..........}\ce{Cl}\phantom{.......}\end{array}\]